JPH08183488A - Pressure damper damping device for hydraulic shock absorber - Google Patents

Abstract

(57) [Summary] [Purpose] Mainly to eliminate the shortage of damping force in the middle and high speed regions so that damping force characteristics close to ideal can be obtained. A center rod 72 is provided in the valve housing so as to be movable in the axial direction and has an oil hole 73 along the central axis, and the center rod 72 is attached to the outer periphery of the center rod 72. 2 First oil chamber 110 and second oil chamber 10 communicating with the lower part and the external tank 8
9 and the intermediate oil chamber 106, and a first leaf valve 98 and a second leaf valve 95, respectively, and an opening of the oil hole 73 communicating with the intermediate oil chamber 106 and the second oil chamber 109. And a needle valve 79 that opens and closes. When the piston rod 4 is in the pressure stroke, the second leaf valve 95 and the needle valve 79 are opened to generate a damping force in the entire speed range, and the second oil chamber 109 and When a differential pressure exceeding the set level between the first oil chambers 110 is generated, the second leaf valve 95 and the first leaf valve 98 are opened to generate the damping force in the medium and high speed regions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure side damping force adjusting device for an external tank type hydraulic shock absorber for suspending a rear wheel of a motorcycle.

[0002]

2. Description of the Related Art As a conventional pressure-side damping force adjusting device for a hydraulic shock absorber of this type, there is one proposed by the present applicant in Japanese Patent Application No. 6-6897.

This is connected between the cylinder 2 and the external tank 8 of the hydraulic shock absorber 1 as shown in FIG.

First, the hydraulic shock absorber 1 includes a cylinder 2 formed of a closed cylinder, a piston 3 for partitioning the inside of the cylinder 2 into upper and lower oil chambers A and B, and an upper end of the cylinder 2 from the piston 3. The shock absorber main body 5 is constituted by the piston rod 4 which penetrates and extends outward.

From the lower side surface of the cylinder 2 of the shock absorber main body 5, a valve housing 6 is integrally formed and protrudes obliquely downward. The valve housing 6 has a connecting passage 7 to connect the valve housing 6 with the valve housing 6. An external tank 8 is connected to the lower oil chamber B of the cylinder 2 through the inside.

The piston 3 which divides the inside of the cylinder 2 into upper and lower oil chambers A and B is provided with an expansion side damping force generating valve 9 and a pressure side rear valve 10, and communicates the upper and lower oil chambers A and B through a piston rod 4. A needle valve (not shown) that is adjustably arranged through a knob 11 from the outside in the sub oil passage
It has.

Further, the compression side damping force adjusting device 12 is housed in the valve housing 6 which is integrally formed with the shock absorber main body 5 described above.

The hydraulic shock absorber 1 has a connecting bracket 1 at the lower end of the cylinder 2 and an upper end of the piston rod 4, respectively.
3 and 14, which are mounted between the vehicle body of the motorcycle and the rear fork through the connecting brackets 13 and 14, and are interposed between the cylinder 2 and the spring receivers 15 and 16 provided on the piston rod 4. The suspension spring 17 elastically supports the vehicle body with respect to the rear wheel.

As a result, when the shock absorber main body 5 expands and contracts due to the vibration between the rear wheel and the vehicle body during traveling, the shock absorber main body 5 is provided through the expansion side damping force generating valve 9 of the piston 3 and the piston rod 4 in the expansion stroke. With the needle valve in the sub oil passage, a flow resistance is given to the working oil from the upper oil chamber A toward the lower oil chamber B, and the extension side damping force is generated by this flow resistance.

At this time, in the lower oil chamber B,
Along with the withdrawal of the piston rod 4 from the cylinder 2, the amount of hydraulic oil corresponding to the withdrawal volume of the piston 2 becomes insufficient. The insufficient amount of hydraulic oil is supplied from the external tank 8 to the communication passage 7 and the compression side damping force adjusting device 12. Is replenished to the lower oil chamber B without resistance.

On the other hand, in the compression stroke, hydraulic oil is flowed from the lower oil chamber B to the upper oil chamber A through the back valve 10 provided on the piston 3 and the needle valve provided on the piston rod 4, and the back valve 10 and the needle valve are connected to each other. While applying back pressure to the lower oil chamber B, the amount of hydraulic oil corresponding to the amount of intrusion of the piston rod 4 from the lower oil chamber B is applied to the communication passage 7
And, it is pushed out to the external tank 8 side through the compression side damping force adjusting device 12.

Then, from this lower oil chamber B to the external tank 8
The pressure-side damping force adjusting device 12 gives a flow resistance to the hydraulic oil directed to the side, and the flow-side resistance of this hydraulic oil generates a pressure-side damping force.

FIG. 5 shows a conventional example of the compression side damping force adjusting device 12 described above. The compression side damping force adjusting device 12 is a ring nut 1 screwed to the valve housing 6.
It has a center rod 19 supported by 8.

The ring nut 18 sandwiches the spring receiver 20 between the ring nut 18 and the valve housing 6 at the tip end surface thereof, and seals the ring nut 18 from the housing 6 by a seal 21 fitted on the outer peripheral surface thereof.

From one side of the spring receiver 20,
An extension portion having a groove 22 formed therein extends along the inner peripheral surface of the ring nut 18, and the ring nut 1
8, the tip end side of the adjustment dial 23 is rotatably sandwiched, and the base end side of the adjustment dial 23 projects to the outside of the valve housing 6.

The base end side portion of the center rod 19 is a bulging portion 19a having a protrusion 24 and a screw 25 on the outer peripheral surface thereof, and the protrusion 24 is engaged with a groove 22 formed in an extension portion of the spring receiver 20. And is screwed to the adjusting dial 23 through the screw 25.

As a result, the center rod 19 can be moved only in the axial direction without rotating due to the engagement between the protrusion 24 of the bulging portion 19a and the groove 22 of the spring receiver 20, and the adjustment dial 23 can be rotated from the outside. By doing so, the screw 25 reciprocates.

A piston body 28 having a compression side port 26 and an extension side port 27 is disposed on the outer periphery of the center rod 19, and the outer peripheral surface of the piston body 28 is brought into sliding contact with the inner wall of the valve housing 6 and The inside of the valve housing 6 is divided into two oil chambers b and c by a seal 29 provided on this outer peripheral surface.

The oil chamber b communicates with the lower oil chamber B of the shock absorber body 5 through the communication passage 7 on the shock absorber body 5 side, and the oil chamber c
Also communicate with the external tanks 8 through the other communication passages 7, respectively.

A through oil passage 30 is bored along the axial center of the center rod 19, one end of the through oil passage 30 opens into the oil chamber b, and the other end of the through oil passage 30 expands 19 of the center rod 19.
The chamber 31 formed in a communicates with the oil chamber c through two ports 32 and 33 that are also provided in the bulged portion 19a.

A main valve 34, a slide collar 35, a washer 36, a collar 37, a valve stopper 38, a spacer 39, and a sub valve 40 are laminated on the outer periphery of the center rod 19 between the piston body 28 and the bulging portion 19a. It is arranged.

Similarly, a slide collar 42 in which a check valve 41 is loosely mounted and a valve stopper 4 are provided on the outer periphery of the center rod 19 on the front end side with the piston body 28 interposed therebetween.
3 are stacked on each other.

The respective members arranged in layers on the outer circumference of the center rod 19 are fixed by being sandwiched between the center rod 19 and the bulging portion 19a by a nut 44 screwed on the tip end side of the center rod 19.

The check valve 41, which opens during the extension stroke of the shock absorber main body 5 and allows the flow of hydraulic oil supplied from the external tank 8 toward the shock absorber main body 5, is normally provided with a valve stopper 43. It is pressed against the piston body 28 by a spring 45 interposed between the piston body 28 and the extension side port 27 of the piston body 28 is closed.

On the other hand, the sub-valve 40 is pushed and bent by the hydraulic oil pushed from the shock absorber body 5 toward the external tank 8 during the compression stroke of the shock absorber body 5,
The restoring force imparts flow resistance to the hydraulic oil to generate a compression-side damping force from the middle half of the low speed range to the middle half of the middle speed. Normally, the port 32 in the bulging portion 19a of the center rod 19 is used. Is blocking the exit part of.

When the sub-valve 40 is bent, the valve stopper 38 on the back side has a function of limiting the maximum amount of bending of the sub-valve 40, restricting the maximum opening area thereof, and preventing the sub-valve 40 from being damaged due to excessive bending. Fulfill

Similarly, when the compression speed of the shock absorber body 5 enters the high speed region from the latter half of the middle speed region during the compression stroke of the shock absorber main body 34, the main valve 34 is pushed by the hydraulic fluid and bends, and the restoring force thereof restores the middle speed region. The compression side damping force is generated from the latter half to the high speed range.

A valve stopper 46 is loosely inserted around the outer periphery of a slide collar 35 provided on the back surface of the main valve 34, and the valve stopper 46 is movable along the slide collar 35 while the washer 36 limits the lift amount. I am doing it.

A valve spring 47 is interposed between the valve stopper 46 and the spring receiver 20. The valve spring 47 presses the main valve 34 against the piston body 28 via the valve stopper 46, and the main valve 34 is pressed. The pressure side port 26 of the piston body 28 is kept closed by the.

As a result, when the main valve 34 is bent, the valve stopper 46 also contacts the washer 36 and is locked by the lift amount.
4 serves to limit the maximum amount of bending of the valve 4, limit the maximum opening area thereof, and prevent damage due to excessive bending of the main valve 34.

On the other hand, a holding cylinder 48 is integrally screwed into the bulging portion 19a of the center rod 19 with the base end protruding outward from the opening side of the valve housing 6, and the adjusting dial 23 described above is Seals 49 and 50 are interposed between the outer circumference of the holding cylinder 48 and the inner circumference of the ring nut 18 so as to be slidable.

Inside the holding cylinder 48, a needle valve 52, which is screwed forward and backward by a screw 51, and a seal 53.
An adjusting knob 55 is rotatably held by a retaining ring 54 that is press-fitted through the inside.

The adjusting knob 55 is provided with a seal 56 between itself and the retaining ring 54, can be rotated from the outside through the retaining ring 54, and is positioned by a detent mechanism 57 interposed between the retaining knob 48 and the holding barrel 48. It is like this.

The needle valve 52 and the adjusting knob 55 are connected to each other by a tongue and groove joint 58.

A variable orifice 59 is formed between the needle valve 52 and the oil passage 74 between them.

The variable orifice 59 is provided in the shock absorber body 5.
During the compression stroke, the flow of the working oil toward the external tank 8 is allowed before the sub-valve 40 is bent, and the compression side damping force is generated in the extremely low speed range particularly in the low speed range.

Next, the operation of the compression side damping force adjusting device 12 will be described. It corresponds to the piston rod intrusion volume integral pushed out from the lower oil chamber of the shock absorber body 5 during the compression stroke of the hydraulic shock absorber 1. A certain amount of hydraulic oil flows into the oil chamber b of the valve housing 6 through the communication passage 7 with the valve housing 6.

The hydraulic oil flowing into the oil chamber b pushes the main valve 84 open, and the chamber 31, the orifice 59 and the bulging portion 19 are also opened from the through oil passage 30 of the center rod 19.
A sub-valve 40 is pushed open from the port 32 as it is via the port 33 of a, and each tries to flow into the oil chamber c.

However, among these three flow paths, the flow resistance from the port 33 directly to the oil chamber c through the orifice 59 has the smallest flow resistance, so that the working oil is first passed through the orifice 59 and then the working oil flows through the orifice 59. It begins to flow toward c.

In this case, when the compression speed of the hydraulic shock absorber 1 is within a very low speed range, which is particularly slow in the low speed range, the oil chamber b
The flow resistance of the orifice 59 is small because the flow rate of the working oil flowing from the oil chamber to the oil chamber c is extremely small.
The hydraulic pressure does not become so high.

Therefore, the main valve 34 and the sub-valve 40 do not bend due to their rigidity, and the pressure side port 26 of the piston body 28 and the bulging portion 19a of the center rod 19 are not deformed.
The port 32 is kept closed.

Thus, during the compression operation of the hydraulic shock absorber 1 in the very low speed range, all the hydraulic oil pushed out from the lower oil chamber B of the shock absorber body 5 to the oil chamber b of the valve housing 6 is at the center. From the oil passage 30 through the rod 19 to the chamber 31
Then, the oil flows into the oil passage 74 through the orifice 59 and further flows from the oil chamber c through the port 33 of the bulging portion 19a to the external tank 8 through the communication passage 7.

Therefore, the compression side damping force in the very low speed range is
The hydraulic oil is generated only by the flow resistance when passing through the orifice 59, and the flow resistance of the hydraulic oil passing through the orifice 59 is effective as the square of the flow rate flowing therethrough.

As a result, the compression side damping force in the very low speed range is
It rises with the square characteristic of the compression speed along the throttle characteristic of the orifice 59.

On the other hand, when the compression speed of the hydraulic shock absorber 1 is in the speed range higher than the above-mentioned very low speed range even in the low speed range,
The flow rate of the hydraulic oil passing through the orifice 59 increases, and the flow resistance of the orifice 59 squares, and the hydraulic oil pressure sharply increases accordingly.

The hydraulic oil pressure is applied to the main valve 3
Before reaching the set pressure of 4, when the set pressure of the sub valve 40 set lower than that is reached, the sub valve 40 first opens before the main valve 34,
The hydraulic oil begins to flow through the sub valve 40 together with the orifice 59.

As a result, the compression-side damping force characteristic from the middle part of the first half of the low speed range rises along the valve characteristic of the sub valve 40.

Next, when the compression speed of the hydraulic shock absorber 1 exceeds the first half of the middle speed range and enters the high speed range, and the hydraulic oil pressure reaches the set pressure of the main valve 34, this time,
The main valve 34 opens together with the sub-valve 40, and hydraulic oil also starts to flow from this point.
The characteristics mainly depend on the valve characteristics of the main valve 34.

Therefore, even if the opening area of the orifice 59 is set small and the compression side damping force characteristic in the very low speed range is improved, the compression side damping force characteristic from the first half of the low speed range to the first half of the medium speed range is It is controlled by the valve characteristic of the sub-valve 40 without being raised too much by the orifice 59. Therefore, by properly selecting the opening area of the orifice 59 and the valve characteristic of the sub-valve 40, the compression side damping force characteristic from the first half of the low speed range to the first half of the medium speed range Can be kept at a desired value.

In the above, the adjustment knob 5 is externally applied.
When the needle valve 52 is rotated through 5 and the needle valve 52 is screwed or unscrewed by the screw 51, the opening area of the orifice 59 changes, whereby the compression side damping force characteristic in the very low speed range is externally adjusted. .

Moreover, the operation of changing the opening area of the orifice 59 does not have any influence on the main valve 34.

Similarly, for the compression side damping force characteristics from the latter half of the medium speed range to the high speed range, the center rod 19 is acted by the screw 25 by turning the adjusting dial 23 from the outside.
Reciprocates in the axial direction, and accordingly, the valve spring 47 interposed between the valve stopper 46 of the main valve 34 and the spring receiver 20 fixed to the valve housing 6 side expands and contracts, and the initial load of the valve spring 47 is increased. It is adjusted by changing.

Therefore, the damping force characteristic from the first half of the low speed range excluding the very low speed range to the first half of the medium speed range is kept low by the sub-valve 40, and at the same time, from the very low speed range and from the latter half of the medium speed range to the high speed range. Adjusting the damping force characteristics 5
5 and the adjustment dial 23 can be rotated independently to make individual adjustments.

Also, slide collars 35 having different heights are used.
Use the washer 36 and the main valve 3 according to it.
It is also possible to preset the valve characteristics of the main valve 34 and the sub valve 40 by changing the thicknesses of the sub valve 40 and the sub valve 40.

Further, the slide collar 35 and the collar 37
The position of the washer 36 is selected by changing the respective heights of the washers 36 without changing the total height of the washers 36.
By changing the lift amount of the valve stopper 46 by selecting the maximum opening area of the main valve 34,
The valve characteristic of the main valve 34 can be changed.

[0056]

However, in such a conventional pressure side damping force adjusting device for a hydraulic shock absorber, the compression speed of the hydraulic shock absorber 1 is increased from the first half of the middle speed range to the high speed range together with the sub valve 40 and the main valve. Since the compression side damping force characteristic is obtained by opening the hydraulic fluid 34 and flowing the hydraulic oil, as shown in FIG. 6, the damping force characteristic by the sub valve 40 and the orifice 50 is different from the required ideal damping force characteristic A. The damping force characteristic +, which is a parallel combination of the damping force characteristic of the main valve 34 and the damping force characteristic, has a problem that the damping force characteristic decreases from the middle speed range to the high speed range.

Even if the damping force of the main valve 34 is increased like the damping force ', it does not reach the above-mentioned ideal damping force characteristic A, and as a result, a shock at the time of landing after a jump is generated. There was a problem that it could not be absorbed.

On the other hand, when the damping force by the sub-valve 40 and the orifice 59 is increased so as to satisfy the ideal damping force characteristic A in the above-mentioned medium-high speed region, this time, conversely, from the low-speed region to the medium-speed region. Then, as indicated by the shaded area K in FIG. 7, there is a problem that a damping force exceeding the damping force characteristic A is generated, resulting in poor riding comfort.

The invention of claim 1 is made by paying attention to the above-mentioned problems, and it is possible to obtain a damping force characteristic close to an ideal, mainly by eliminating the shortage of the damping force in the middle and high speed regions. It is an object to obtain a compression side damping force adjusting device for a hydraulic shock absorber.

According to the second aspect of the invention, the spring load is adjusted by the movement of the center rod to adjust the first oil chamber and the second oil chamber.
It is an object of the present invention to provide a pressure side damping force adjusting device for a hydraulic shock absorber that enables adjustment of the differential pressure between the oil chambers and that can arbitrarily adjust the damping force in the medium and high speed ranges.

According to a third aspect of the present invention, the first oil chamber and the second oil chamber are provided through the orifice opened and closed by the needle valve.
It is an object of the present invention to obtain a pressure side damping force adjusting device of a hydraulic shock absorber capable of generating an arbitrary damping force in a low / medium speed range while a set differential pressure is generated between the oil chambers.

It is an object of the present invention to provide a pressure side damping force adjusting device for a hydraulic shock absorber capable of compensating for the reduction of the damping force in the medium and high speed range which occurs with the temperature rise of hydraulic oil.

[0063]

SUMMARY OF THE INVENTION A compression side damping force adjusting device for a hydraulic shock absorber according to the present invention is provided in a valve housing so as to be axially movable, and a center rod provided with an oil hole along a central axis. And a first leaf valve attached to the outer periphery of the center rod, which separates a first oil chamber, a second oil chamber, and an intermediate oil chamber, which communicate with the lower portion of the cylinder in the valve housing and the external tank, respectively. A second leaf valve, and a needle valve that opens and closes an opening of the oil hole that communicates with the intermediate oil chamber and the second oil chamber, and during the pressure stroke of the piston rod, the first leaf valve and A damping force is generated in the entire speed range through the needle valve, and the second leaf valve is opened when the pressure difference between the second oil chamber and the intermediate oil chamber exceeds a set level. In middle or high speed region is obtained so as to generate a damping force.

According to a second aspect of the present invention, there is provided a compression side damping force adjusting device for a hydraulic shock absorber, which is provided with an initial load adjusting means for adjusting the spring pressure for the second leaf valve by adjusting the axial movement amount of the center rod. Is.

According to the third aspect of the present invention, the compression side damping force adjusting device for the hydraulic shock absorber is provided with the opening / closing amount adjusting means for adjusting the opening / closing amount of the needle valve with respect to the opening of the oil hole. According to a fourth aspect of the present invention, in the compression side damping force adjusting device for a hydraulic shock absorber, an oil storage chamber for storing temperature compensating oil is provided on the back surface of the needle valve.

[0066]

According to the first aspect of the present invention, in the compression side damping force adjusting device for the hydraulic shock absorber, the total amount of oil press-fitted from the lower portion of the cylinder during the pressure stroke of the piston rod in the cylinder is passed through the first leaf valve and the needle valve. , When it is introduced to the external tank side to generate the desired damping force in the full speed range, while a pressure difference between the first oil chamber and the intermediate oil chamber that exceeds the set level occurs at the needle valve section, , Above second
The leaf valve of is opened so that the damping force in the high speed range can be obtained at the time of landing in a jump, for example.

In the pressure-side damping force adjusting device for the hydraulic shock absorber according to the second aspect of the present invention, the differential pressure between the intermediate oil chamber and the second oil chamber is adjusted to an arbitrary value by adjusting the initial load on the spring by the movement of the center rod. The size can be set so that the damping force in the high speed range can be arbitrarily approximated to the ideal value.

According to the third aspect of the present invention, in the compression side damping force adjusting device for the hydraulic shock absorber, the flow rate of the working oil for generating the differential pressure between the intermediate oil chamber and the second oil chamber is controlled by the needle valve, that is, the orifice. It can be arbitrarily adjusted by the opening / closing amount of the needle with respect to the opening end of the oil hole provided at the center rod center.

In the pressure-side damping force adjusting device for the hydraulic shock absorber according to the fourth aspect of the present invention, the needle valve is displaced in the axial direction by the expansion of the temperature compensating oil in the oil accommodating chamber, whereby the temperature of the oil rises to the middle and high speed regions. Make sure to compensate for the decrease in damping force at.

[0070]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described with reference to the drawings. In FIG. 1, reference numeral 6 denotes a valve housing connected between the cylinder 2 and an external tank 8. The cylinder-shaped guides 61 and 62 having a recess for forming the oil passage 63 on the outer peripheral side are connected and arranged.

The guide 61 is provided with an oil hole 64 penetrating in and out of the guide 61, and a spring receiver 65, which will be described later, is provided on the inner peripheral surface of one end of the guide 61 so as to receive the spring.

The guide 62 is in contact with the bottom portion of the valve housing 6 on the side opposite to the guide 61 side, and a seal 66 is provided on the outer peripheral surface near the contact portion, through which a seal is provided. The outer circumference of the guide end closely contacts the inner circumference of 6.

Further, 67 is an oil hole provided at the end of the guide 62 so as to penetrate the inside and outside of the guide 62, and this oil hole 67 is formed on the stopper 68A of the non-return spring 6.
A check valve 69 supported by 8 can open and close.

Further, a ring nut 71 having a seal ring 70 on its outer periphery is screwed into the inner periphery of the valve housing 6 on the open end side, the inner end of which contacts the outer end of the guide 61, This is held on the valve housing side.

Reference numeral 72 is a center rod having an oil hole 73 along the central shaft portion, and a projecting piece portion 74 projecting on the outer periphery of the middle abdominal portion of the central rod portion abuts the outer end of the spring receiver 65. A part of a cylinder-shaped notch case 75 is screwed onto the outer periphery of the protruding piece 74, and is integrally connected to the center rod 72.

The center rod 72 has a large diameter needle valve sliding hole 76 which communicates with the oil hole 73 in the central shaft portion.
An adjuster insertion hole 77 having a diameter larger than that of the needle valve sliding hole 76 is continuously provided.

In the needle valve sliding hole 76, a needle valve 79 forming an orifice 78 for opening and closing the end of the oil hole 73 is provided movably in the axial direction, while in the adjuster insertion hole 77, The protrusion 82 formed at one end is inserted into the locking hole 80 on the rear surface of the needle valve 79, and the adjuster 81 as the opening / closing amount adjusting means for operating this in the rotating direction is housed.

Reference numeral 83 is an oil hole provided in the center rod 72 and penetrating in and out of the end of the oil hole 73, and 84 is an oil hole penetrating the middle part of the center rod 72 for accommodating the needle valve 76. It is possible to communicate with the oil hole 73 when the orifice 78 is opened.

Reference numeral 85 is an adjuster as an initial load adjusting means which is rotatably slidably provided in the ring nut 71 through a seal ring 86. The notch case 75 is provided on the inner circumference of the inner end side of the adjuster. The outer periphery of a part of is screwed.

A thrust washer 87 faces the slit 89 for moving the protruding piece 74.

On the inner peripheral surface on the outer end side of the adjuster 85,
The outer peripheral surface on the outer end side of the notch case 75 is in sliding contact with the seal ring 88.

Then, the notch case 75 and the adjuster 8
A seal ring 92 and a detent mechanism for positioning the adjuster 81, which is composed of a spring 90 and a ball 91, are interposed between the first and second positions.

On the other hand, on the outer circumference of the center rod 72 on the side where the oil hole 73 is located, a spacer 93 and a slide collar 9 are provided.
4, second leaf valve 95, valve seat 96, cylinder type valve stopper 97, first leaf valve 9
8. The valve seat 99 is sequentially fitted and inserted, and these are pressed and held by the nut 100 screwed into the end of the center rod 72.

Further, 110 is a first valve which is separated by a valve seat 99 in the valve housing 6 on the cylinder 2 side.
Is the oil chamber.

A spring guide 101 having a flange portion for pressurizing the second leaf valve 95 is slidably installed on the outer periphery of the slide collar 94, and the space between the spring guide 101 and the spring receiver 65 is increased. A spring 102 is interposed in the.

Further, 103 is an oil hole provided in the valve seat 99 and blocked by the first leaf valve 98, and 104 is this oil hole 103 and the second leaf valve 9.
5 is a small cutout orifice formed between the two.

Reference numeral 105 denotes an oil hole penetrating the inside and the outside of the valve stopper 97. The oil hole 83 communicates with the oil hole 73 of the center rod 72 and the two valve seats 9 are provided.
It communicates with the intermediate oil chamber 106 formed between 6 and 99.

Further, 107 is an oil hole provided in the valve seat 96 and closed by the second leaf valve 95.

A second oil chamber 109 is formed between the valve seat 96 and the projecting piece portion 74, and communicates with the external tank side through the oil hole 64.

Next, the operation will be described. Cylinder 2
The direction in which the hydraulic oil flows between the external tank 8 and the external tank 8 in accordance with the compression stroke and the extension stroke of the piston rod 4 is basically the same as that shown in the above-mentioned conventional example. And a desired damping force is generated.

That is, according to the present invention, in the compression stroke, the hydraulic fluid sent from the cylinder 2 side is the first
Through the oil chamber 110, the total amount of oil enters the intermediate oil chamber 106 through the oil hole 103 of the valve seat 99 and the orifice 104 opened by the first leaf valve 98.

The hydraulic oil that has entered the intermediate oil chamber 106 enters the oil hole 73 through the oil hole 105 of the valve stopper 97 and the oil hole 83 of the center rod 72, and is further opened and closed by the needle valve 79. It is sent into the second oil chamber 109 via the orifice 78 and the oil hole 84.

The hydraulic oil in the second oil chamber 109 is fed into the external tank 8 through the oil hole 64.

As a result, the first leaf valve 98 described above is used.
2 and the orifice 104, damping force characteristics in the low, medium, and high speed regions as shown in FIG.
By the orifice 78 whose opening is adjusted by 9, the damping force characteristic as shown in FIG. 2 is obtained.

The hydraulic oil that has entered the intermediate oil chamber 106 remains in the intermediate oil chamber 106 until the pressure difference between the second oil chamber 109 and the second oil chamber 109 exceeds a set level, and the needle valve 79 is used. When the pressure difference due to the orifice 78 exceeds the set level, the second leaf valve 95 receiving the initial load by the spring 106 is pushed open to be discharged from the oil hole 107. The hydraulic oil flows into the second oil chamber 109.

That is, the damping force in the medium and high speed range generated by the flow of the hydraulic oil through the second leaf valve 95 becomes like the damping force characteristic in FIG.
FIG. 2 shows the damping force characteristic (parallel combination) combined with this and the damping force characteristic obtained in the needle valve 78.

Therefore, the damping force characteristic + which is a combination of the above two damping force characteristics and the damping force characteristic is close to the ideal damping force characteristic A in FIG. 2 and the conventional damping force characteristic is insufficient as shown in FIG. Can be improved.

In other words, the damping force characteristic + can set the damping force in the middle and high speed regions to a value close to ideal without generating extra damping force as shown in FIG. 7 in the low speed region.

Further, according to the present invention, by rotating the adjuster 85, the notch case 75 screwed into the inner peripheral surface of the adjuster 85 moves axially.

As a result, the center rod 72 integrally connected to the notch case 75 moves in the same direction, and the initial load of the spring 102 interposed between the spring guide 101 and the protruding portion 74 on the center rod 72 is adjusted. enable.

Therefore, with this initial load adjustment, the first
Regardless of the leaf valve 98 and needle valve 79 of
The load of the second leaf valve 95 can be adjusted,
Mainly, it enables arbitrary and easy setting of damping force in the middle and high speed regions.

On the other hand, by rotating the adjuster 81, the needle valve 79 whose locking hole 80 is engaged with the projection 82 is rotated in the axial direction along the needle valve sliding hole 76 of the center rod 72. While moving.

Therefore, the opening degree of the orifice 78 can be finely adjusted, and the speed at which the set pressure difference is reached is mainly adjusted.

FIG. 3 shows another embodiment of the present invention. In this embodiment, the outer end of the center rod 72A is held in the ring nut 71A, and the center rod 71A is held.
The axial load of the spring 102, that is, the initial load adjustment from the outside of the spring 102 is made impossible, and the initial load adjustment can be performed only by adjusting the thickness of the washer 200.

Further, in this embodiment, the needle valve 7 is installed in the valve housing member 111 which houses the needle valve 79 in the center rod 72A slidably in the axial direction.
An oil storage chamber 120 filled with temperature compensating oil is formed so as to be in contact with the back surface of the container 9.

On the back surface of the valve housing member 111, a protrusion 112 fitted to an adjuster 81 whose front end faces the outer end of the valve housing 6 is in contact, and the adjuster 81 is rotated together with the protrusion 112. By operating, the needle valve 79 together with the valve housing member 111 can be axially moved by a screw.

Further, the adjuster 81 has the guide member 1 screwed to the end of the ring nut 71A via the spring 113 and the ball 114 constituting the detent mechanism.
15 It is linked to the inner surface.

The other components similar to those shown in FIG. 1 are designated by the same reference numerals, and the duplicated description will be omitted.

In this embodiment, the same operation and effect as those shown in FIG. 1 can be obtained, but the temperature rise of the working oil reduces the viscosity of the working oil, thereby reducing the damping force. Even in the case of inviting, the temperature increase is used to expand the temperature compensating oil in the oil storage chamber 120, thereby moving the needle valve 79 in the axial direction and opening the opening degree of the oil hole 73 ( It is possible to suppress the orifice opening) to a small value and increase the damping force.

That is, the damping force in the middle and high speed regions can be maintained near a substantially constant ideal value regardless of changes in the viscosity of the hydraulic oil, regardless of changes in the ambient temperature.

[0111]

As described above, according to the first aspect of the present invention, the center rod provided in the valve housing so as to be movable in the axial direction and provided with the oil hole along the central axis,
A first valve attached to the outer circumference of the center rod and communicating with the lower part of the cylinder in the valve housing and the external tank.
Leaf valve and second leaf valve that respectively define the oil chamber, the second oil chamber, and the intermediate oil chamber, and the opening of the oil hole that communicates with the intermediate oil chamber and the second oil chamber. And a needle valve for adjusting a portion of the piston rod, and a damping force is generated in the entire velocity range through the first leaf valve and the needle valve during the pressure stroke of the piston rod, and the damping force is generated between the second oil chamber and the intermediate oil chamber. When a differential pressure exceeding the set level is generated, the second leaf valve is opened to generate damping force in the middle and high speed range, so the lack of damping force in the middle and high speed range is mainly eliminated, making it ideal. There is an effect that it is possible to obtain one that can obtain a similar damping force characteristic.

According to the second aspect of the present invention, since the initial load adjusting means for adjusting the spring pressure to the second leaf valve by adjusting the axial movement amount of the center rod is provided, the center rod is moved by the movement. By adjusting the spring load, the differential pressure between the intermediate oil chamber and the second oil chamber can be adjusted, and the damping force in the medium and high speed range can be arbitrarily adjusted.

According to the third aspect of the invention, since the opening / closing amount adjusting means for adjusting the opening / closing amount of the needle valve with respect to the opening of the oil hole is provided, the first valve is opened via the orifice opened / closed by the needle valve. Oil chamber and second
There is an effect that an arbitrary damping force can be generated in the low / medium speed range in the state where the set differential pressure is generated between the oil chambers.

According to the fourth aspect of the present invention, since the oil accommodating chamber for accommodating the temperature compensating oil is provided on the back surface of the needle valve, the damping force in the middle and high speed regions which occurs with the temperature rise of the working oil. The effect of being able to compensate for the decrease in

[Brief description of drawings]

FIG. 1 is a sectional view showing a compression side damping force adjusting device for a hydraulic shock absorber according to an embodiment of the present invention.

FIG. 2 is a damping force characteristic diagram showing a damping force generated in each part of the pressure side damping force adjusting device for a hydraulic shock absorber according to the present invention.

FIG. 3 is a sectional view showing a compression side damping force adjusting device for a hydraulic shock absorber according to another embodiment of the present invention.

FIG. 4 is a sectional view showing a hydraulic shock absorber according to the present invention.

FIG. 5 is a cross-sectional view showing a conventional compression side damping force adjusting device for a hydraulic shock absorber.

FIG. 6 is a damping force characteristic diagram showing a damping force generated in each part of the conventional pressure side damping force adjusting device for a hydraulic shock absorber.

FIG. 7 is a damping force characteristic diagram showing a damping force generated in each part of the conventional pressure side damping force adjusting device for a hydraulic shock absorber.

[Explanation of symbols]

 2 cylinder 4 piston rod 5 hydraulic shock absorber body 6 valve housing 8 external tank 72 center rod 73 oil hole 79 needle valve 81 adjuster (opening and closing amount adjusting means) 85 adjuster (initial load adjusting means) 95 second leaf valve 98 first Leaf valve 106 Intermediate oil chamber 109 Second oil chamber 110 First oil chamber 120 Oil storage chamber

Claims (4)

[Claims] 1. A valve housing provided continuously between a cylinder lower part of a hydraulic shock absorber body and an external tank,
In a pressure side damping force adjusting device of a hydraulic shock absorber that stores hydraulic oil corresponding to an intruding volume of a piston rod in the cylinder in the external tank while generating a damping force, it is possible to move axially in the valve housing. A center rod provided with an oil hole along the central axis, and a first oil chamber and a second oil chamber which are attached to the outer periphery of the center rod and communicate with the cylinder lower part and the external tank in the valve housing. Leaf valve and a second leaf valve that respectively define the oil chamber and the intermediate oil chamber, and a needle valve that opens and closes the opening of the oil hole communicating with the intermediate oil chamber and the second oil chamber. And a damping force is generated in the entire speed range through the first leaf valve and the needle valve during the pressure stroke of the piston rod, and the second Chamber and a differential pressure in the event of exceeding set levels between the intermediate oil chamber, a hydraulic shock absorber compression side damping force adjusting device that generates a damping force in middle or high speed range by opening the second leaf valve. 2. The pressure-side damping force adjusting device for a hydraulic shock absorber according to claim 1, further comprising an initial load adjusting means for adjusting a spring pressure for the second leaf valve by adjusting an axial movement amount of the center rod. 3. The compression side damping force adjusting device for a hydraulic shock absorber according to claim 1, further comprising opening / closing amount adjusting means for adjusting the opening / closing amount of the needle valve with respect to the opening of the oil hole. 4. The pressure side damping force adjusting device for a hydraulic shock absorber according to claim 1, wherein an oil storage chamber for storing temperature compensating oil is provided on the back surface of the needle valve.